Palladium catalyzed codimerization process

ABSTRACT

Solid pi -allyl complex catalysts comprising: A. A palladium source; B. A monotertiary phosphine electron donor ligand; C. A combination of a reducing agent capable of reducing the palladium source to an oxidation state of less than 2 and a Lewis acid capable of forming a coordination bond with palladium; and D. An acidic, solid, silica-based support material, are useful in the codimerization of a conjugated diene and a monoene. Preferably, the catalyst is activated by the additional presence of a conjugated diene. In a preferred embodiment, the solid pi -allyl palladium complex catalyst prepared from palladium acetylacetonate, triphenylphosphine, diethylaluminum chloride and a calcined silica-alumina support having a separate, distinct alumina phase is useful in the selective codimerization of 1,3-butadiene and ethylene to form trans-1,4hexadiene.

United States Patent Ronald L. Milam, Media, Pa.

Assignee: Atlantic Richfield Company, Philadelphia, Pa.

Filed: Jan. 2, 1973 v Appl. No.1 320,164

Related US. Application Data Continuation of Ser. No. 53,654, July 9,abandoned.

References Cited UNITED STATES PATENTS 8/1968 Schneider 260/680 7/1971Cannell..... .;.260/683.l5

Yoo et al. Nov. 18, 1975 PALLADIUM CATALYZED Primary E.\'aminerPaul M.Coughlan, Jr.

CODIMERIZATION PROCESS Attorney, Agent, or Firm-Thomas J. Clough [75]Inventors: Jin Sun Yoo, South Holland, [1].;

[57] ABSTRACT Solid rr-allyl complex catalysts comprising:

A. A palladium source;

B. A monotertiary phosphine electron donor ligand;

C. A combination of a reducing agent capable of reducing the palladiumsource to an oxidation state of less than 2 and a Lewis acid capable offorming a coordination bond with palladium; and

D. An acidic, solid, silica-based support material, are useful in thecodimerization of a conjugated diene and a monoene. Preferably, thecatalyst is activated by the additional presence of a conjugated diene.In a preferred embodiment, the solid 'rr-allyl palladium complexcatalyst prepared from palladium acetylacetonate, triphenylphosphine,diethylaluminum chloride and a calcined silica-alumina support having aseparate, distinct alumina phase is useful in the selectivecodirnerization of 1,3-butadiene and ethylene toformtrans-1,4-hexadiene.

9 Claims, No Drawings PALLADIUM CATALYZED CODIMERIZATION PROCESS This isa continuation of application Ser. No. 53,654, filed July 9, 1970, nowabandoned.

This invention relates to novel ir-allyl complex catalyst compositionsand their use in the polymerization of olefins. In particular aspects,the invention relates to solid, 'rr-allyl-complex catalyst compositionscomprising a palladium source, a combination of a reducing agent capableof reducing the palladium source to an oxidation state of less than 2and a Lewis acid capable of forming a coordination bond with palladium,a monotertiary phosphine electron donor ligand and an acidic, solid,silica-based material and the use thereof in the codimerization ofconjugated dienes with monoenes to form l,4-dienes.

Homogeneous catalysts comprising a palladium compound, an aluminumalkylhalide reducing agent and compounds of a Group V-A or VI-A element areknown in the art and have previously been utilized in thedimerization of1,3-dienes with ethylene to form trans l,4-dienes. US. Pat. No.3,398,209 discloses that such catalysts exhibit catalytic activity inthe preparation of trans 1,4-dienes. The preparation of the trans isomerin substantial yields is advantageous because the trans isomers ofl,4-dienes are useful in preparing vulcanizable terpolymers withethylene and propylene.

Numerous disadvantages are, however, attendant the use of suchhomogeneous catalysts in the preparation of trans-1,4-dienes, and theuse of the solid catalysts described herein is advantageous in a numberof these respects. The use of the solid catalysts in a fixed bed, slurryor other form eliminates the necessity for the separation of the solublecatalytic species from the products and thus eliminates catalyst lossesoccurring during such separation. Also, since the catalytic speciesherein is firmly fixed upon the acidic, solid, silica-based materialthrough either a coordination bond or an electrostatic ionic bond formedthrough an ion exchange mechanism, the catalyst is remarkably stable,even after extended exposure to the atmosphere, and the deposition ofmetallic palladium attendant the use of the soluble homogeneous catalystspecies is thus minimized. Furthermore, since the level of catalyticactivity exhibited by the solid catalysts is higher than in thehomogeneous counterpart catalysts, reduced reaction or contact times maybe used.

In short, the acidic, silica-based material employed in the solidcatalysts is not only an effective supporting matrix for the'rr-allylpalladium complexes prepared in situ in the system to give anactive solid catalyst, but also the support acts as a cocatayst.

Additionally, if inactivated, the solid catalyst of this invention iseasily reactivated by the addition of a fresh portion of reducing agentLewis acid or monotertiary phosphine electron donor ligand or acombination of these two components. This ease of reactivation isattributable at least in part to the firm fixation of the metal sourceto the support material and resultant catalyst stability. Also, sincethe solid catalyst is useful in a fixed bed, slurry or other form,economic, continuous prouction of trans-1,4 dienes is achieved. Anotheradvantage of the present catalyst is the versatility thereof in bothliquid phase and vapor phase reactions.

It has ben found that 'n-allyl complex catalyst compositions of apalladium source, a monotertiary phosphine electron donor ligand andacombination of a Lewis 2 acid capable of forming a coordination bondwith palladium and a reducing agent capable of reducing the palladiumsource to an oxidation state of less than 2, when supported on anacidic, solid, silica-based material, provide catalysts of highlydesirable physical and chemical characteristics for an improvedpreparation of trans l,4-dienes from conjugated dienes and monoenes. Toobtain such compositions, the catalyst forming reactants can be combinedin a molar ratio of electron donor ligand to palladium of about 0.5 to15:1, preferably about 1 m3 to 10:1 or even about 3 to 5:1; and a Lewisacid-reducing agent to palladium molar ratio of about 2 to 40:1,preferably about 5 to 12:1. The amount of Lewis acid-reducing agent toelectron donor ligand can vary in more or less direct proportion withthe molar ratio of electron donor to palladium source. The molar ratioof Lewis acid-reducing agent to electron donor ligand can often bebetween about 0.5 to 15:1, preferably between about 1 to 10:1. Theweight ratio of acidic, solid, silica-based support material topalladium source normally varies between about 2' to 2000: 1, preferablyabout 5 to 200:1 and most advantageously between about 10 to 50:1.

In the preparation of the catalyst compositions of the presentinvention, the palladium is provided by compounds of the metal which arepreferably at least partially soluble in some solvent wherein palladium,monotertiary phosphine electron donor ligand and Lewisacid-reducingagent combination complex or a palladium and monotertiaryphosphine electron donor ligand complex can be formed. Preferred are theweak field ligand complexes, the ligands of which readily serve insolution as transfer agents. Suitable sources of the palladium caninclude, for example, inorganic salts and bases such as PdCl PdBr PdlPdSO Pd(Ol-l) PdCl .2KCl and Pd(NO l) dihydrocarbyloxy palladiumcompounds of the formula Pd(OR) wherein R is an alkyl, aryl, aralkyl ora like group and combinations thereof; hydrocarbyloxy palladiumcarboxylates of the formula (RO) Pd OOCR, wherein R and R are as definedabove for R; and phosphine complexes such as diphosphine complexes ofthe formula Pd[(C H PC H P(C l-l ]X wherein X is a halide. Also,available as a palladium source are chelates formed by palladium andweak field ligands such as ,8- diketones and B-keto carboxylic acids,esters and salts thereof. Examples of these palladium sources incudeB-diketonato palladium (ll), acetylacetonato palladium (II),propionylacetonato palladium (ll), benzoylacetonato palladium (ll);other chelates from B- keto carboxylic acids, esters and salts thereof;salts of saturated monocarboxylic acids, e.g. palladium formate,palladium propionate, palladium caproate, palladium octoate, palladiumpalmitate, palladium stearate and the like; salts of correspondingunsaturated monocarboxylic acids, e.g., palladium acrylate, palladiummethacrylate, palladium oleate and the like; salts of sat urateddicarboxylic acids, e.g., palladium adipate, palladium succinate,palladium decane-1,l0-dicarboxylate and the like; salts of correspondingunsaturated dicarboxylic acids, e.g., palladium muconate and the like;salts of cyclic and aromatic carboxylic acids, e. g., palladiumcyclohexane carboxylate, palladium benzoate, palladium phthalates; andpalladium dialkoxycarboxylates, e.g., palladium dimethoxyacetate.Preferred sources of palladium are those wherein the R and R groupscontain less than about 10 carbon atoms. A particularly advantageoussource of palladium is palladium 3 acetylacetonate.

The Lewis acid and the reducing agent functions of the catalysts of thisinvention are preferably supplied in a single compound. As examples ofsuchcompounds there may be mentioned the acidic metal halides whichcorrespond to the general formula:

R,,,.,,)MX,.. wherein M is a metallic element of coordination number nwhose halides are Lewis acids, X is a halogen having an atomic number of9 to 53, i.e., fluorine, chlorine, bromine, iodine, R is hydrocarbyl ofup to about 20 carbon atoms, particularly alkyl groups of 2 to about 10carbon atoms and is a number having a value from 1 to at least one lessthan n so that at least one R hydrocarbyl group is present. Preferredmetallic elements in the above formula include aluminum, magnesium,beryllium, mercury, lead, zinc, and tin. A particularly advantageousmetal is normally aluminum. Examples of suitable acidic metal halidesinclude alkylaluminum halides including mono-, sesqui-, and dihalides.Specific examples of suitable alkylaluminum halides are diethylaluminumchloride, fluoride, iodide, and bromide; ethylaluminum dichloride;ethylaluminum sesquichloride, etc.

Where the particular reducing agent employed in the composition does notalso perform as a Lewis acid, it is necessary to separately supply theLewis acid to the catalyst composition. Examples of reducing agentswhich are suitable in the preparation of the catalyst composition butwhich do not perform as Lewis acids themselves includetrialkylaluminums, monoalkoxydialkylaluminums and dialkylaluminumhydrides wherin the alkyl and alkoxy groups contain up to about 10carbon atoms. Other examples are Grignard reagents, allyl and alkyl tincomplexes, and the like. The reducing agent should be compatible withthe Lewis acid and capable of reducing the palladium source,advantageously palladium acetylacetonate, to an oxidation state lowerthan 2, preferably even to 0.

The Lewis acid component can be supplied by a compound which is otherthan a protonic or hydrogen acid and which is capable of receiving oneor more pairs of electrons to form a coordination bond. Lewis acids arewell known to the art and are defined for example by Noller, Chemistryof Organic Compounds, W. B. Saunders, 1951, at pages 233235, by Stone,Chemical Review (1958) at page 101, and by G. N. Lewis, Journal of theFranklin Institute 1938), pages 226-293. Examples of Lewis acids whichare not included as a component of a compound which also serves as areducing agent include boron-trifluoride, boron-trifluoride etherates,e.g., diethyletherate, aluminum trihalides, zinc halides and stannichalides.

The electron donor ligand component of the catalysts of this inventionare monotertiary phosphines of the formula (R) P where R is anessentially hydrocarbyl group of 1 to about carbon atoms, optionallysubstituted with non-deleterious groups. Preferably R is a hydrocarbongroup selected from alkyl, including cycloalkyl, alkaryl, aralkyl andaryl groups of up to about 20 carbon atoms. Exemplary of such groups areethyl, isobutyl, hexyl, decyl, octadecyl, cyclohexyl, benzyl, phenyl,tolyl, and naphthyl. Trialkyl phosphines wherein the alkyl groupscontain less than about 10 carbon atoms such as tri-n-butyl phosphineand triaryl phosphines such as triphenylphosphine 'have been found to beparticularly advantageous.

The solid supports suitable for use in the catalysts of this inventionare acidic, solid, silica-based materials, e.g., having a D L activityof at least about 20, preferably at least about 30, when determinedaccording to the method of Birkhimer et al., A Bench Scale Test Methodfor Evaluating Cracking Catalysts," Proceedings of the AmericanPetroleumInstitute, Division of Refining, Vol. 27(111), page (1947) andhereinafter referred to'as Cat A. The silica-based support preferablyhas a substantial surface area as determined by the BET nitrogenabsorption procedure (JACS, Vol. 60, pp. 309 et seq., 1938). The surfacearea of the support can be at least about 50 square meters per gram, andsuch surface areas'are often up to about 500 or more m /gm, preferablyabout to 400 m /gm. It is preferred that the catalyst support berelatively dry to avoid undue reaction with and loss of catalyticpromoting materials. Thus it is advantageous that the support becalcined, e.g., at temperatures of about 600 to 1500F. or more, toreduce the water content, but such calcination should not be so severethat the support is no longer catalytically active.

The support component can contain other materials in addition to silicawhich materials, when combined with silica, provide an acidic materialas in, for instance, the case of silica-alumina. Often these materialsare one or more oxides of the metals of Groups II, III and IV of thePeriodic Table. Examples of the composites contemplated herein under thegeneric designation of silica-based materials are often composedpredominantly of or even to a major extent of silica. These-supportsinclude, for example, silica-alumina, silica-boria, silica-zirconia,silica-magnesia, silica-alumina-zirconia, silica-alumina-thoria,silica-alumina-magnesia, and the like. The silica-based support cancontain amorphous or crystalline materials such as a crystallinealuminosilicate, for instance, having pore openings with diameters inthe 6 to 15 Angstrom unit range. The support often contains silica andalumina, and such supports, whether naturally-occurring as inacid-treated clays, or a synthetic gel, will frequently contain about 10to 60, preferably about 15 to 45, weight percent alumina. In addition,such silica-alumina supports can, and preferably do, contain a portionof the alumina as a separate, distinct phase.

A highly preferred catalyst support can be made by combining asilica-alumina hydrogel with a hydrous alumina with or without(preferably without) a crystalline aluminosilicate. An advantageoushydrous alumina component is, when analyzed by X-ray diffraction of dry.samples, either one or a mixture of amorphous hydrous alumina and amonohydrate, e.g., boehmite, of less than about 50 A, preferably lessthan about 40 A, crystallite size as determined by half-widthmeasurements of the (0,4,1) X-ray diffraction line calculated by theDebye-Scherrer equation. The mixture of the catalyst precursorcomponents can be dried, e.g., at about 220 to 500F., to provide theactive catalyst support. During calcination, the separate hydrousalumina phase of the mixture is converted to a gamma form or othercatalytically-active alumina.

In providing the preferred catalyst support precursor for drying, thecomponents can be combined in any suitable manner or order desired, andadvantageouly each of the components in the mixture is in finely dividedform, preferably the particles are principally less than about 300 meshin size. The finely divided material can have an average particle sizeof about 10 to 150 microns and can be used to make a catalyst of thisparticle size which canbe employed in a fluidized bed type of operation.However, if desired, the rnixtureofcata lyst supportcomponents can beplaced inmacrosized form, that is,made into particles as by tabletting,ex

truding, etc., to sizes of the order of about N64 to k inch or more indiameter and about 1/32 to 1 inch or more in length, before or afterdryingor calcination. If

formation of the macrosized particles is subsequent to,

calcination and the calcined particle'shave been con-: tacted withwater, the mat'erialcan be recalcin ed.

On a dry'basis, the preferred supports of the catalysts of the presentinvention contain about 45 to 95 weight percent of the amorphoussilica-alumina xerogel, about 5 to 55 weight percent of the separatelyaddedalumina phase, and about 0 to 50 weight percent of the c'rystallinealuminosilicate, preferably the proportions of these ingredients areabout 75 to 90%, about to 25% and about 0 to respectively. If present,the crystalline aluminosilicate is usually at least about 1 weightpercent, preferably at least about'5 weight percent,- based on the driedsupport. The alumina content from the silica-aluniina xerogelandthe'separate alumina phase is about 20 to 70 weight percent, preferablyabout to 60 weight percentfbased on the dried support. Also,

the catalyst'support generally contains less than about 1.5 weightpercent, preferably less than about 0.5 weight percent, sodium.

The silica-alumina component of the.precursor of the I preferredcatalyst support of the present invention can be silica-alumina hydrogelwhich contains about 5.5 to

6* In preparing the catalyst support, we may separately filter thesilica-alumina hydrogel and the hydrous alu- -mina and intimatelymixthese, materials, for instance,

by colloidal milling. Although in-this particular procedure a low sodiumcontentcrystalline aluminosilicate can be added after the milling, thisingredient can also be combined before the ,colloid al millingoperation.

' The mixture is dried, water washed to acceptable concentrations of,.for instance,.sodium, and redried in the preferred procedure. Thedrying, especially the initial.

1 drying, isadvantageouslyeffected by spray drying to give microspheres.

The vcrystalline aluminosilicate which can be present in catalystsupport of the present invention, can have pore openings of about 6m 15A in diameter and preferably the pore openings have adiameter of about 8or ,10 to 14A. Usually, with a given material, the poresare relatively.uniformjn size and often the crystalline alu- 90, preferably 65 to 75,weight percent silica and about 10 to 45', preferably about 25 to 35,weight percent alumina, on a dry basis. The silica-alumina can benaturally occurring or can be synthetically prepared by any desiredmethod and several procedures are'known in the art. For instance, anamorphous silica-alumina hydrogel can be prepared by co-precipitationorsequential precipitation by either component being the initialmaterialwith at least the principal part of the silica or alumina being made inthe presence of the other. Generally the alumina is precipitated in thepresence of a. silica gel. It is preferred that the silica-aluminahydrogei be made by forming a silica hydrogel by precipitation from analkali metalsilicate solution and an acid such as sulfuric acid. Thenalum solution may be added to thesilica hydrogel slurry. The alumina isthen precipitated by raising the pH into the alkaline range by the 1addition of an aqueous ,sodiumaluminatesolution or by t the addition of.a base such as ammonium hydroxide. Other techniques for preparing thesilica-alumina hydrogel are well known in the art, and these techniquesmay be used in the practice of the invention.

The alumina hydrogel which canbe combined with the silica-alumina ismade separately from the silicaalumina. The alumina hydrogel may beprepared, for example, by precipitation of alumina at alkaline pH'bymixing, alum withsodium aluminate inan aqueous solu--' tion or-with abase such as soda ash, ammonia, etc. As noted above the alumina hydrogelcan bein the form of amorphous hydrous alumina or alumina monohydrate,

e.g., of up to about 50 crystallite size asdetermined by X-raydiffraction analysis. The amorphous hydrous alumina generallycontains asmuch Qc'orhbinfed water as does an alumina monohydrate. Mixtures of themono hydrate and amorphous forms ofvhydr oi isgalumina' are preferredand often this phase iscom'posedfof atleast about 25% of each of theseparate members.

soluble; ammonium compound. Subsequently, during drying and/or,calcination, the ammonium ion may break down to release ammonia andleave an acid site on the aluminosilicate. On a'molar basis the ammoniumor hydrogenion is usually at least about 10% or even at least about 50%,based on the alumina content of the I crystalline aluminosilicate.Suiitable replacements forthe sodium also include the polyvalent metalsof the pe- 1 riodic chart, including the Group ll-A and rare earth.metals such as cerium, etc. The metals may be present alongwith theammonium or hydrogen cations. I Theorder in which components arecombined to prepare the supported catalyst of the present invention canbe varied. The catalysts can be conveniently prepared by impregnatingthe silica-based support materialwith a solution of the palladiumcomponent, e.g., palladium acetylacetonate, in a solvent, e.g.,methanol. The palv ladium impregnatedsupport, preferably after solventremoval, may then be sequentially contacted with asolution of themontertiary phosphine electron donor ligand component, e.g., triphenylphosphinefand then the reducing agent and Lewis acid component'or components, ,e.g. ethyl aluminum sesquichloride or diethyl aluminumchloride. The catalysts prepared according to this method wherein therr-allyl palladium complex is formed onvthe support material generallyexhibit less activity than the. types described hereinafter wherein therr-allyl complex is prepared in the presense'of a conjugated diene ofthetype used in making the diene- .monene, dimers in accordance with thisinvention, e. g.,

l,3-butadiene.flhe presence of the conjugated diene duringcatalystpreparation is believed to aid formation of an at leastinitially more active catalyst species.

Thus, although the foregoingare methods for preparing the catalysts .ofthis invention, in a first more preferred method the palladium source issupported on the acidic, solid, silica-based material in the presence ofa monotertiary phosphine. electron donor ligand, e.g., tri- 7. phenylphosphine, and subsequently reduced to the active catalyst with theLewis acid-reducing agent components or component, e.g., diethylaluminumchloride, in the presence of a conjugated diene, e.g., 1,3-butadiene. Ina second more preferred method, a rr-allyl palladium complex is preparedfrom a palladium source, e.g., palladium acetylacetonate, a monotertiaryphosphine electron donor ligand, e.g., triphenyl phosphine, and theLewis acid-reducing agent component or components, e.g., diethylaluminumchloride, in an inert solvent in the presence of a conjugated diene,e.g., 1,3- butadiene, before the acidic, solid, silica-based material isadded to the system to fix the palladium source and form an active,stable catalytic species. The cata lysts prepared by the first preferredmethod will hereinafter be referred to as catalyst type A while those ofthe second preferred method will hereinafter be referred to as catalysttype B. The foregoing are two general methods for preparing thepreferred catalysts of this invention, types A and B. Type B hasgenerally been found to be the more advantageous regarding activity andstability of these two types.

More specifically, in the preparation of the B type catalysts, therr-allyl palladium complex is first prepared for subsequent impregnationinto the silica-based support. The preparation of the rr-allyl-palladiumcomplex is normally conducted by mixing a palladium source, an electrondonor ligand and a Lewis acidreducing component in an inert solvent andbubbling a conjugated diene through the system before addition of thesupport. Suitable solvents are those which are inert to the catalyst andwhich will not enter into or deleteriously affect the eventualcodimerization reaction. As specific examples thereof may be mentionedaromatic and aliphatic hydrocarbons such as hexane, benzene, toluene,and various petroleum fractions. Oxygenand halogen-containing solventsare generally to be avoided during the codimerization. Suitable solventsfor the complex-forming reaction thus generally are the same solventswhich are suitable for use with the final catalyst composition in areactive environment. If desired, however, the complexing may beaccomplished in a solvent which is unsuitable for use with the finalcomposition; in this case, the resultant complex can be first isolatedfrom the reaction mixture and re-dissolved or resuspended in a propersolvent which is inert to the final catalyst composition.

The codimerization of conjugated dienes with monoenes to formtrans-1,4dienes using the catalysts herein can be accomplished usingshort reaction times and mild reaction conditions. Various conjugateddienes are useful in the disclosed process, although those 1,3-

dienes having up to about 10 carbon atoms such as butadiene, isoprene,piperylene, l,3-cyclopentadiene and 1,3-cyclooctadiene, including theirhalogen, alkyl and phenyl-substituted drivatives such as chloroprene and2-phenyl butadiene are preferred. Various monoenes are useful, althougholefins of up to about 10 carbon atoms such as ethylene, propylene,irobutylene, pentene-l and other a-olefins are preferred, e.g., alkenes.The reaction may generally be conducted over a wide range oftemperatures'andpressures. Normally, the reaction is conducted in theliquid or gaseous phase at a temperature above room temperature in therange of from about 75F. to about 300F. The reaction is also normallycarried out using pressures greater than atmospheric wherein theadditional pressure is at least partially supplied by the monoenereactant. Thus, the re- 8. action is conducted up to about 5000p.s.i.g., preferably from about 500 p.s.i.g. to 2000 p.s.i.g. Theoptimum combinations of temperature, pressure, reaction time, reactantsand catalyst may be determined from variation of the reactionparameters. The reaction may furthermore be optionally accomplished inthe presence of an inert, organic solvent. Useful solvents arehydrocarbons such as hexane, toluene, benzene, and petroleum fractionsboiling between about l50to 350F. Also, the amount of catalyst presentduring the reaction can vary, but the amount is often from about 0.01 to20% by weight of the reactants. ln continuous reaction systems the spacevelocity may normally be about 1 to 25 WHSV, preferably about 2 to 15WHSV.

The following Examples I to ill relate to the preparation of a preferredtype of solid, silica-based support material, which material has anadditional alumina phase.

EXAMPLE I An alumina hydrogel is prepared as follows:

In a tank containing 5700 gallons of water at F., are dissolved 300 lbs.of soda ash. When the soda ash has been dissolved, 180 gallons of a 39%concentration aqueous sodium aluminate solution are pumped into the tankin about a 15-minute period. The contents of the tank are at about 84F.and 600 gallons of aqueous aluminum sulfate of 7.8% concentration, as A10 are added to the admixture over an 80-minute period with water ofdilution in conjunction with, and in addition thereto, diluting thereaction mass at a rate of 25 gallons per minute.

The pH of the resulting aqueous reaction mass is adjusted to 8.0 withabout 75 gallons of 39% concentration aqueous sodium aluminate solutionwhich, while being added, is also diluted continuously with water at arate of 35 gallons per minute over a 7 minute addition period. Thecontents of the tank are heated to about 100F., and pumped to storage.

The precipitated, hydrated alumina is thereafter filtered on a large gelfilter. The filtered product is partially purified by a one-cycle,water-wash on the filter on which it is collected. This filter is astring vacuum type drum filter with a built-in water spray nozzledirected toward the filter drum. Material on the drum is contacted withwater as the drum rotates past the nozzle. After washing, the wetalumina hydrogel is stripped from the drum. This hydrogel analyzes about50% boehmite having a crystallite size of about 35 A, and 50% amorphoushydrous alumina as determined by X-ray diffraction on dried samples.

EXAMPLE II A silica-hydrogel is prepared by the following technique:

To a batch tank is added 4,275 gallons of water'preheated to F., and 865gallons of sodium silicate solution (28.8 weight percent SiO 404l.5Baume at 68F. and Na O:SiO ratio of 113.2) is added. The batch isstirred for 5 minutes. The concentration of the sodium silicate, as SiOin the batch is 6.3 weight percent.

With the batch at 90F, 302 gallons of 34.5 weight percent sulfuric acidsolution at 182F. are added over a period of 45 minutes. The gel formsabout 35 minutes after acid addition is begun. Then the pH is adjustedto 8.0-8.5. The batch is agitated for 10 minutes.

Then 715 gallons of alum (7.8 weight percent, as Al is added to the gelover a period of about 36 minutes. The batch is agitated for anadditional 5 minutes whereupon 205 gallons of sodium aluminate solution(24.4 weight percent as A1 0 diluted in 1080 gallons of water is addedover a period of 17 minutes. After all the sodium aluminate is added,the pH is checked. It should be between 5.0 and 5.2. The alumina contentof the silica-alumina hydrogel is 3031%.

EXAMPLE 111 The silica-alumina hydrogel product of Example 11 and 1740gallons of the alumina hydrogel filter cake of Example 1 are mixedtogether for 1 hour. The finished batch has a pH of 5.5 to 5.6 and atemperature of about 110F. The aqueous gel mixture is then pumped to adewatering filter, and the filter cake from said dewatering filter and aportion of aqueous gel are blended to give a gel slurry of about 14weight percent solids. A portion of this hydrogel mixture was slurried,as a thick flowable paste, with a Lightnin stirrer fitted with acage-beater and a propellor, for about minutes to give a thoroughdispersion. The product was stirred one minute at 14,500 rpm, in aWaring Blender and dried in a laboratory spray-drier. The spraydriedmaterial was washed with water to acceptable impurity levels and driedat 230F. The washed and dried material analyzed 0.08% S0 and less than25 ppm. Na O. The dried material as such was used as the catalystsupport as were extruded forms thereof and tablets (pellets) havingdiameters of about one-eighth inch and lengths of about one-eighth toone-half inch- Before use the catalyst support was calcined in a mufflefurnace by raising the temperature by 300F. per hour until 1350F. wasreached. This temperature was then held for 3 hours. The calcinedparticles had a surfact area of about 320 to 340 square meters per gram.

The remainder of the Examples are drawn to the preparation of therr-allyl complex catalyst compositions and the use thereof in thecodimerization of conjugated dienes and monoenes, particularly1,3-butadiene and ethylene, to form trans-1,4-dienes, particularlytrans-1,4-hexadiene. The following examples are further indicative ofthe stability of the solid catalysts prepared herein. Tables 1 and 11give further details of catalyst compositions, reaction conditions andproduct distribution.

EXAMPLE IV The preparation of a type A catalyst is accomplished asfollows:

0.32 Grams of palladium acetylacetonate, 1.41 grams oftriphenylphosphine and 5.0 grams of the extrudate silica-alumina supportof Example 111 are mixed in 35 ml. of toluene at room temperature andallowed to stand under a nitrogen atmosphere for about 20 hours. Thesupport extrudate is then washed with about 100 ml. of toluene until acolorless supernatant liquid is obtained. All remaining toluene isdecanted and the pellets are transferred with 25 ml. of fresh toluene toa 300 cc. stainless steel magnedrive autoclave, which is sealed andflushed with purified nitrogen. Then 25 ml. of toluene and 5 ml ofdiethylaluminum chloride (21 36.1% solution thereof in toluene)are'transferred to a 75 cc. nitrogen blanketed stainless steel bombwhich is then sealed and pressured with 400 p.s.i. g. of nitrogen. Tenml. of butadiene is added to the autoclave and the pressurized additionof the contents of the steel bomb 10 to the autoclave is accomplished.The addition of butadiene may also follow the addition of thediethylaluminum chloride.

EXAMPLE V The preparation of a type B catalyst is accomplished asfollows:

10.4 Grams of a 36.1% diethylaluminum chloride solution in toluene isadded to 0.32 grams of palladium acetylacetonate, 1.32 grams oftriphenylphosphine and 20 ml. of butadiene in a benzene solution in anitrogen blanketed dry box at room temperature. Then the butadiene isevaporated off and 5.0 grams of the extrudate silica-alumina support ofExample 111 is added to the homogeneous yellow solution. After remainingopen to the atmosphere for about 48 hours, the dry box is emptied; thenthe solvent is removed and the extrudate pellets are transferred to a300 cc. autoclave which is sealed and flushed with purified nitrogen.

EXAMPLE Y1 As in Example IV, butadiene (10 ml.) is added to the sealedautoclave followed by the pressurized addition of the entire contents ofthe cc. stainless steel bomb as described in Example 1V. Additionalbutadiene (35ml.) is subsequently added to the autoclave followed by 300psig of ethylene. The heater is turned on accompanied by the stirrer andthe reaction begun. A heat-up time of 1 hour is required to bring thetemperature of the system to 180F. This temperature (i 10F.) ismaintained throughout the 21.0 hour reaction time. A pressure range'of850-1050psig is recorded for the 21 hour reaction time. A clear yellowliquid product (88 gms.) is; collected using a dry ice-acetone trap,transferred to a cc. stainless steel bomb, and analyzed by gaschromatography. The calculated butadiene conversion for this reaction isabout 97% with a selectivity to trans-l, 4-hexadiene of 5.3%.Considerable isomerization took place as observed by the conjugate2,4-hexadiene (cis and trans isomers) content (45.1%). Pertinent dataregarding this run are listed in Tables I and 11.

EXAMPLE VII in the manner described in Example IV palladiumacetylacetonate (0.31 gms. and triphenylphosphine (1.34 gms.) aresupported on the silica-alumina extrudate (5.1gms. )ofExample 111. Thesupported pellets are transferred to the 300 cc. magnedrive autoclavealong with fresh toluene (SO-ml), mixed with butadiene (20 ml.), andactivated with diethylaluminum chloride (5 m1. of a 36.1% toluenesolution) in 25 m1 of additional toluene. Ethylene (650 psig) issubsequently added and the heater turned. on accompanied by the stirrer.A heat-up time of about 1.5 hours is required to reach the desiredtemperature of 150F. which is maintained for the 19.5 hour reactionperiod. A pressure of 1200 i 50 psig is also maintained for this periodof time. A yellowtinted product (82 gms.) collected using adryice-acetone trap is slowly warmed to room temperature, providing asample (78.6 gms.) for gas chromatogaphy analysis. The butadieneconversion is approximately 70% and the selectivity totrans-1,4-hexadiene is about 4.0%. The extent of isomerization, althoughless than Example V1, is substantial as witnessed by the 2,4-hexadienecontent (37.5%). As before, all data are listed in Tables I and 11 whichmore completely describe this run.

EXAMPLE VIII As described in Examples IV and VII the heterogeneouscatalyst is prepared from palladium acetylacetonate (0.33 gms.) andtriphenylphosphine (1.39 gms.) using the extrudate (5.0 gms.) of Example[11 in a toluene solvent (50 m.). The supporting pellets are thenactivated in butadiene (25 ml.) with diethylaluminum chloride ml. of a36.1% toluene solution) in 15 ml. of additional toluene in a fashion aspreviously outlined. Additional butadiene (15 ml.) is added to theautoclave containing the above components followed by ethylene (300psig). The heater is turned on accompanied by the stirrer; a 45 min.heat-up period is required to attain the desired temperature of 173F.which is held throughout the 10.5 hour reaction period. The pressure ismaintained at 1 100 i 50 psig throughout. After 10.5 hours reactiontime, the product 155.5 gms) is transferred directly to a 300 cc.stainless steel bomb at dry ice-acetone temperature. The catalyst isretained in the sealed autoclave and the stainless steel bomb at 80C.was slowly vented off (-24 hours) leaving a product (89.5 gms.) which isanalyzed by gas chromatography. The conversion calculates to be 82.3%based on butadiene charged, and the selectivity to transl,4-hexadiene isl 1.0%. The extent of isomerization is about the same as Example VI.Tables I and II contain the data accumulated for this run.

EXAMPLE IX Using the catalyst left in the 300 cc. autoclave from ExampleVII, a second consecutive reaction is begun with butadiene (40 ml.) andethylene (1100 psig). A 45- min. heat-up time is required to reach thesame temperature (173F.) as used in Example VIII. This reaction (10.5hours) is also carried out at 173F. and 1100 psig. After the statedreaction time, the product (67.0 gms.) is treated as explained inExample VIII to provide the final gas chromatographic sample product(26.5 gms.) for analysis. The catalyst is again retained in theautoclave for further use.

The conversion recorded for this reaction is 20.8% and the selectivityto trans-l,-4-hexadiene is 52.1%. As reported in Table I the conversionis reduced from that obtained in example VIII while the selectivity isincreased from Example VIII. Additional comparative data is listed inTable II.

EXAMPLE X Using the catalyst left in the 300 cc. autoclave from ExampleIX, a third consecutive reaction is begun with butadiene (40 ml.) andethylene (1100 psig). Except for a reaction time of 7.5 hours, allconditions of the reaction and work-up procedures are the same. A finalproduct (25.5 gms.) is analyzed by gas chromotography. The conversion(50.0%) is increased over Example IX while the selectivity (51.2%)remains unchanged.

EXAMPLE XI Butadiene (50 ml.) and ethylene 800 psig) are introduced tothe 500 cc. autoclave containing the catalyst of Example V. The heaterand stirrer are turned on and an about hour reaction begun. Atemperature of 170 1 10F. and a pressure of 1300 i 100 psig ismaintained. A yellow colored product (65 gms.) is collected andtransferred to a sampling bomb resulting in a product (59.8 gms.) whichis analyzed by gas chromatography. The catalyst from this reaction isremoved from the autoclave and stored in air for two hours after use.The conversion calculated for this reaction is 43.8% and the selectivityto the transl 4-hexadiene is 65.5%. The extent of isomerization iscomparatively low (13.1%) as reflected by the conjugated C content.Tables I and II contain additional pertinent data.

EXAMPLE XII After being stored for 2 hours in an air atmosphere thecatalyst employed in Example X1 is transferred back to the 300 cc.autoclave along with additional triphenylphosphine (1.32 gms.),butadiene (40 ml.), and toluene (50 ml.). Diethylaluminum chloride (5ml. of a 36.1% toluene solution) is added followed by ethylene (-650psig), and the heater and stirrer are turned on for a second consecutivereaction. The conditions for this reaction are comparable to Example XIand are listed in Table I. Both the conversion (300%) and selectivity(51.6%) for this reaction decrease from the first run (Example XI).Additional comparisons may be found in Tables I and II.

EXAMPLE XIII To a 250 ml. four-neck flask are added palladiumacetylacetonate (0.33 gms.), triphenylphosphine (1.36 gms.) andchloroform ml.) and the system is flushed with prepurified nitrogen.Butadiene (-25 ml.) is subsequently added until a steady reflux isobtained from the dry iceacetone cold finger. Diethylaluminum chloride10 ml. of a 36.1% toluene solution) is added to give ahomogeneous-yellow solution. Approximately 2 hours later the extrudateof Example III (5.0 gms.) is added, and the system is maintainedovernight with a slow nitrogen bleed (-20 hours). The liquid is decantedfrom the pellets and the pellets rinsed with about 50 ml. of chloroformuntil a colorless supernatant liquid is obtained. The residualchloroform is removed from the pellets under a vacuum of about 10 mm.for about 5 min. and the dried pellets are introduced into theautoclave. The autoclave is sealed and flushed well with nitrogen.Butadiene ml.) is added to the reactor followed by ethylene (500 psig).The heater and stirrer are turned on and approximately 1 hour isrequired to heat the system to the desired temperature (176F.). At thistemperature a pressure of 1200 i 100 psig is maintained throughout thefour hour reaction period. The product from this reaction is pressurizedinto a 300 cc. stainless steel bomb and the ethylene is then slowly bledoff leaving a product mixture (84.5 gms.) which is analyzed by gaschromatography. The conversion is 55.8% with a selectivity of 44.4% tothe trans-1,4-hexadiene. Isomerization to the conjugated diolefin isstill substantial as shown by the 2,4-hexadiene content (31.0%). Allother recorded data from this experiment may be found in Tables I andII.

EXAMPLE XIV Using the same procedure as outlined in Example XIII, thecatalyst is prepared from palladium acetylacetonate (0.32 gms.),triphenylphosphine (1.38 gms.), butadiene (-35 ml.), and diethylaluminumchloride (10 ml. of a 36.1% toluene solution) in toluene (50 ml.)solvent. 5.0 Grams of the extrudate of Example 111 is added to the abovesystem and retained for about 20 hours. After freeing the solvent fromthe pellets, they are transferred to the autoclave which is then sealedand flushed with nitrogen Butadiene (140 ml.) is

. added along with ethylene (400 psig). The heater and stirrer areturned on and a heat-up time of one hour is required to reach thedesired temperature (175F.) for l the 6 hour reaction. A continuousethylene pressure (1200 psig) is maintained throughout the reactionperiod. A sample of the reactor liquid phase is taken immediately afterthe above-mentioned heat-up time. Additional samples are similarly takenevery 1.5 hours for the complete reaction period. These samples are thenanalyzed by gas chromatography. Results from these samplings arerecorded in Tables I and II.

EXAM PLE XV Palladium acetylacetonate (0.32 gms.), triphenylphosphine1.34 gms.), and toluene ml.) are placed in an autoclave which is sealedand flushed with nitrogen. Butadiene (100 ml.) is then added. A mixtureof toluene (10 ml.) and diethylaluminum chloride (10 ml. of a 36.1%toluene solution) is then added followed by ethylene (500 psig). Theheater and stirrer are turned on and a pressure of 1200 -100 psig ismaintained along with a temperature of 175F. for a 4 hour reactionperiod. The product is collected in a 300 cc. stainless steel bombcontaining dilute I-ICI (25 gms.). The ethylene is vented off, and theseparated product phase (48 gms.) is analyzed by gas chromatography. Theconversion based on butadiene charged is calculated to be 17.5% and theselectivity to trans-1,4-hexadiene 37.5%. The extent of isomerization issubstantial as indicated by'the content of 2,4-hexadiene (35.0%). TablesI and 11 contain information recorded for this experiment.

EXAMPLE XVI To examine the extent of the isomerization of 1,4- dieneproducts by the rr-allyl palladium complex supported on the'extrudate'of Example 111, the "same run described in Example XIV isduplicated over a 3.75

hour period by taking four samples from the system as reactionprogressed. Palladium acetylacetonate (0.35

g.), 1.32 g...triphenylphosphi-n'e, and 50. ml. chloroform Y are placedin a 250 ml. flask giving a yellow homogeneous solution.' Butadiene isthen added until a steady reflux is obtained off a dry ice-acetonecold'finger under 114 flask. The contents of the flask are stirredovernight a1- lowing the excess amount of unreacted butadiene toevaporate off. The resulting tan colored catalyst extrudates arefiltered and washed with about 100 ml. of chloroform until a colorlesssupernatant liquid is obtained. These steps are carried out under anitrogen atmosphere. The resulting tan colored catalyst pellets aredrained of solvent and put under vacuum to remove as much solvent. aspossible. The catalyst pellets are charged in a 300 cc. autoclaveequipped with a mag netic stirrer, and both butadiene (140 ml.) andethylene (400 psig at room temperature) are fed to the autoclave. Theheater and stirrer are turned on and within 40 minutes the reactorreaches a temperature of 161F. and a pressure of 1 140 psig. Foursamples (-1 ml.) are taken out of the reactor duringthe time span of 3hours to study the extent of isomerization of the trans-1,4- dieneproduct and of the conversion of the butadiene Y feed. These samples aresubjected to the gas chromatoa nitrogen atmosphere. Diethylaluminumchloride (20 3 refluxing conditions for a 2 hour period, the yellow '11-allyl complex solution of palladium ispoured on to'5.0 grams ofextrudate of Example 111 iri=a Erlenmeyer graphic analyses. The resultsare listed in Tables 1-11. The data clearly indicates that theisomerization of 1,4- dienes to 2,4-isomer takes place rapidly as thecontact time of the reaction mixture to the catalyst lengthens, and thatthe conversion of the butadiene feed (91 g.) increases from 8% to 26%during a 3 hour reaction period.

EXAMPLE XVII The catalyst used in the. reaction of Example XVI is agedunder an ethylene atmosphere for 35 days. The

reaction of Example XVI is then substantially duplicated. The results ofthe reaction with this aged catalyst are summarized in Tables I and I1and indicate clearly that the aged catalyst is still an active catalyst.

A study of the data presented in Tables 1 and I1 indicates that catalystType A gives a less selective reaction to the desired 1,4-hexadieneproducts and less isomerization of the trans-l,4-diene to conjugateddiene products, particularly 2,4-dienes, then does catalysttype B.

.Again, it is believed this reduced activity is due to the absence ofconjugated diene during catalyst formation. Thus, using Catalyst A adiene is present only when the codimerization is initiated. Furthermore,the extent of isomerization of trans-1,4-hexadiene to 2,4-hexadienesincreases with the length of reaction as indicatedby Examples XIV andXVI. Also, the 2,4-dienes then appear to react with another ethylenemolecule to give a 1,4- diene; in this particular case the 1,4-diene is3-n'iethyl- 1,4 hepta'diene. Examples X1 and X11 indicate that theexposure to the atmosphere.

TABLE 1 Example Catalyst Composition Reaction Conditions No. 1 Pd(acac)d P Et -AICI Alumina-Silica Solvent Time Temperature Pressure g. g. g.Support g. I -1r. ,F. Psig.

V1 0.32A 1.41 1.62 5.0 43.0 21.0 170-192 850-1050 VII 0.31A 1.34 1.625.1 64.5 19.5 1200 VIII 0.33A 1.39 1.62 5.0 43.0 10.5 173 1100 1X 0.33A1.39 1.62 5.0 43.0 10.5 173 1100 X 0.33A 1.39 1.62 5.0 43.0 7.5 v 1731100 XI 0.32B 1.32 3.75 5.0 43.5 19 -182 1300 X11 0.32B 1.32 1.62 5.086.0 18 -185 1500-1700 X111 0.338 1.36 3.2 5.0 4.0 176 1200 XIV 1. 0.3281.38 3.2 5.0 0.0 1200 2. 0.32B 1.38 3.2 5.0 3.0 175 1200 3. 0.32B l.383.2 5.0 4.5 175 1200 4. 0.32B l.38 3.2 5.0 6.0 175 1200 XV 0.323 1.343.2 12.0 4.0 175 1200-1300 XVI 1. 0.3513 1.32 6.4 5.0 0.75 160 1100Pressure Psig.

Reaction Conditions Time Temperature Hr. F.

Pd( acac 1.. gv

Example e Au iss w ajo i bfiss i n n. 005556 oollll WW LC 7- d a urR H 4L J .2 .9 .9 .65 H 053446557555944446 0 (J mm n n m m A3 .5 .2 .9 lll m478997300 8081.454 O k 5a; lllll ll 1 7 e 3 m m s sszassssszsjsz 4i Wx90023362152 2 4530 VC-M l til l 3 lll 000 666% l 111 e c a mm m M 1264.1. n hm 2 1 0 1 230 0 o N u m BB 0 51.45 60343702 563 a t 7 5 2 .9 617 5 14 9 1 l lll 3 3343 l l m u u 3.5 2212 1 .5 m H 000 141111 0000 r se l P n .l .m H5 2A B .8 .2 E 0000 0 0000 0000 L X B e A H 4. 31 .0.5193AJ113141 T 002 2087676640 236 00 00 -\!-\..V-5

4. a biassasyzjss azs 4 1 43386797 803 t .556544433345564 r r0 4 44 Wm 00 5 6 4 8 927 569938 6666 n i 54 2 41l867d lom 1 mwmflw 5 50 5444333455W4 t a fl 3333 mw mvfl 1 1 1] v n 3 3 -J2 .52 .0 n 5020030578078.0068 787-5435 6009 a -l BBB )))))1 00 5555 2 1 VA XW XXX l mmmm peuamsas44a4maaama D m8 000050000000 .000 m O3666265 5 F 222 269999699998114 9 1- 7-afi4 1-34 AB to l N l 1 1 1 l V fC [H H 10" VV V X ABVV\|XXXXX XX X 4. A process of claim 1 wherein the composition isfurther activated by contact with a conjugated diene of g up to about 10carbon atoms.

5. A process of claim 4 wherein the reactants are butadiene and ethyleneand the product is trans-1,4-hexadiene.

6, A process of claim 4 wherein the reaction temperature is from about75 to 300F. and the pressure is up to about 5000 psig.

-7.'A process of claim 1 wherein (A) is supplied by palladiumacetylacetonate; (B) has the formula P(R) wherein R is an alkyl group ofup to about 10 carbon atoms or phenyl; (C) is an alkyl aluminum halideand (D) is calcined silica-alumina having a distinct, separate aluminaphase.

8. A process of claim 7 wherein the reactants are butadiene and ethyleneand the product is trans-1,4hexl,4-hexadiene..

9. A process of claim 7 wherein the reaction temperature is from about75 to 300F. and the pressure is up to about 5000 psig.

It is claimed:

1. In a process for the codimerization of a conjugated diene with analkene to a trans-1,4-diene in the presence of a catalyst, theimprovement comprising usin as a catalyst a minor amount of rr-allylcomplex of:

A. palladium,

B. monotertiary phosphine electron donor ligand,

and

C. combination of reducing agent capable of reducing the palladium to anoxidation state of less than 2 and Lewis acid capable of forming acoordination bond with palladium, supported on D. acidic, solid,silica-based material; wherein the molar ratio of(B) to (A) is fromabout 0.5 to 15:1 the molar ratio of (C) to (A) is from about 2 to 40:1and the rr-allyl complex is formed from a conjugated diene.

2. A process of claim 1 wherein the reactants are butadiene and ethyleneand the product is transadiene.

3. A process of claim 1 wherein the reaction temperature is from aboutto 300F. and the pressure is up to about 5000 psig.

1. IN A PROCESS FOR THE CODIMERIZATION OF A CONJUGATED DIENE WITH ANALKENE TO A TRANS 1,4-DIENE IN THE PRESENCE OF A CATALYST, THEIMPROVEMENT COMPRISING USING AS A CATALYST A MINOR AMOUNT OF $-ALLYLCOMPLEX OF: A. PALLADIUM, B. MONOTERTIARY PHOSPHINE ELECTRON DONORLIGAND, AND C. COMBINATION OF REDUCING AGENT CAPABLE OF REDUCING THEAPLLADIUM TO AN OXIDATION STATE OF LESS THAN 2 AND LEWIS ACID CAPABLE OFFORMING A COORDINATION BOND WITH PALLADIUM, SUPPORTED ON D. ACIDIC,SOILD, SILLICA-BASED MATERIAL; WHEREIN THE MOLAR RATIO OF (B) TO (A) ISFROM ABOUT 0.5 TO 15:1, THE MOLAR RATIO OF (C) TO (A) IS FROM ABOUT 2 TO40:1 AND THE $-ALLYL COMPLEX IS FORMED FROM A CONJUGATED DIENE.
 2. Aprocess of claim 1 wherein the reactants are butadiene and ethylene andthe product is trans-1,4-hexadiene.
 3. A process of claim 1 wherein thereaction temperature is from about 75* to 300*F. and the pressure is upto about 5000 psig.
 4. A process of claim 1 wherein the composition isfurther activated by contact with a conjugated diene of up to about 10carbon atoms.
 5. A process of claim 4 wherein the reactants arebutadiene and ethylene and the product is trans-1,4-hexadiene.
 6. Aprocess of claim 4 wherein the reaction temperature is from about 75* to300*F. and the pressure is up to about 5000 psig.
 7. A process of claim1 wherein (A) is supplied by palladium acetylacetonate; (B) has theformula P(R)3, wherein R is an alkyl group of up to about 10 carbonatoms or phenyl; (C) is an alkyl aluminum halide and (D) is calcinedsilica-alumina having a distinct, separate alumina phase.
 8. A processof claim 7 wherein the reactants are butadiene and ethylene and theproduct is trans-1,4-hexadiene.
 9. A process of claim 7 wherein thereaction temperature is from about 75* to 300*F. and the pressure is upto about 5000 psig.